Process and apparatus for scavenging internal-combustion engines.



s. w. STEVENS. PROCESS AND APPARATUS FOR SGAVENGING INTERNAL COMBUSTION ENGINES.

APPLICATION FILED AUG. 6, 1809 Patented Apr. 25, 1911.

[QM/ 6: W. firm/[Ms UNITED STATES PATENT OFFICE.

ELBB-IDGE W. STEVENS, OF BALTIMORE, MARYLAND.

PROCESS AND APPARATUS FOR SCAVENGING INTERNAL-COMBUSTION ENGINES.-

990,604. Driginal applicationfiled July s, 1969,-

Specification of Letters Patent. Patented Apr. 25, 1911- Serial No. 507,925. Divided and this application filed August 6,

1909. Serial No. 511,532.

To all whom it may concern:

Be it known that I, ELBRIDGE W. STEVENS, a citizen of the United States, residing at Baltimore city, in the State of Maryland,

have invented certain new and useful Improvements in Processes and Apparatus for scavenging Internal-Combustion Engines, of which the following is a specification, the same being a divisional application of my original ap lication filed July 16, 1909, Serial No. 50 ,925.

In the scavenging of the burned gasesfrom the combustion chamber of internal cornbustionengines, it is very necessary 1n to completely discharge, all the burnedgases, or products of combustiombefore introducing the next fuel charge, for otherwise the remnants of such gases prevent the proper filling of the combustion chamber with the full volume of the next charge and such remaining s ent gases, being inert, dilute the charge an lower its efiiciency. In two-cycle engines especially does this difiiculty exist, since the conditions of its operation involve either imperfect scavenging on the one hand, or the loss of a considerable part of the combustiblefuel charge on the other.

This invention is designed to secure a perfeet scavenging of the burned gases, and to that end it embodies a process of scavenging by an introduced volume of air which has two phases of displacement of the gases, one

'following the other and acting in continued sequence, that .is to say, the initial introduction of the air is discharged into a central zone of the combustion chamber and this infiowing stream. is immediately afterward diverted into the other or outer concentric zones, to completely sweep out all the burned v gases Th s process is carried out in a simple and practice way by an adaptation of the end of the combustion chamber to the opening movement of the air intake valve, as here:

' inafter more fully described with reference to the drawingf in which, the ii are is a vertleal sectlon 0 take air valve at the top which opens by sue enging.

f n the drawing a cover B isscrewed to the top of the explosion cylinder 1.; A ringshape walve seat B is detachably held in securing the hi hestefliciency of the engine,

through the holes h in the the top part 0- a two-cycle. gas engine cylinder with a 'spring-seated in the top of the explosion cylinder and has a radial projection B extending to the center and terminating in an upright sleeve B The valve seat has a beveled edge 8 that rests" upon a corresponding beveled shoulder on the inner edge of the cylinder and a screw threaded retaining ring B is screwed into an interior screw thread in the upper end of tlie cylinder and holds the valve seat B in p ace.

B is the air inlet valve of large-size, nearly filling the upper end of the cylinder. This has a stem B extending up through the sleeve B and is provided with a cap or nut B against which bears a spiral spring B which holds the valve B up against its seat.

In the interior of the cylinder, at the top and immediately adjacent to the valve seat, is a circular roove or enlargement of the cylinder forming an inwardly projecting circula'r lip a which is concentric with the valve seat and just a little below the same but of larger diameter than the valve.

12 is the pipe through which compressed, air enters the cylinder. As the-air is forced or sucked in through pipe 12, it passes into an annular channel in I the cylinder and valve seat B and forces open the valve B At the first downward movement of this valve, the air issues in a circular radiating sheet into the (groove formed above the lip a and is imme iately deflected inwardly again, by'the lip, toward the center, as shown by the full line arrows d and the converging currents produce a vortex or whirlwind action at d down through the central zone or core, so to speak, of the cylinder, and as the valve B opens wider to the dotted position, it asses the deflector lip a, as shown by the otted lines, since it is of smaller diameter than said lip and has a range of movement past it, and then the air, without any inward deflection, passes down through the outer zone of the cylinder, as indicated by the dotted arrows 6, so that the result attained is a complete sweeping out of the whole cross" section of the cylinder,

of air currents, first by a central vortex ion by two phases combustion engine, which consists in introducing into the combustion chamber air currents at points of entry concentric to the axis of the cylinder and following this with other air currents also concentric to the axis of the cylinder but in a different coaxial zone.

2. The process of scavenging an internal combustion engine, which consists in introducing, into the combustion chamber, air currents at points of entry concentric to the axis of the cylinder and diverting these air currents from one zone of the combustion chamber to another concentric zone, to sweep out the entire cross section of the chamber.

3. The process of scavenging an internal combustion engine, which consists in introducing into the central zone of the combus.- tion chamber air currents forming a gyratory vortex and immediately afterward introducing diverging. air currents along the inner walls of the cylinder.

4., An internal combustion engine having a convergent neck with a valve seat and inwardly opening valve, said neck bemg formed with an inwardly projecting annular lip inside the valve seat and said valve being arranged to pass by the said lip to give two directions 0 incoming air currents.

5. An internal combustion engine having an inwardly opening intake air valve and an annular and concentric air deflector surrounding the same, the intake valve being arrangedto pass thev deflector on the opening movement. a

6. An internal combustion engine having a convergent neck with a valve seat and an inwardly opening valve, said neck being formed with an inwardly projecting annular lip, inside the valve seat and said ,Valve being arranged to pass by the said lip to give two directions 0 incoming air currents, a Cap for closing the neck of the cylinder, a valve seat within thesame having a tubular guide to receive the stem of the valve and a spiral spring wrappedaround the same and arranged to hold up the valve stem and maintain the valve closed with a yielding pressure.

In testimony whereof I aflix my signature in presence or two witnesses.

ELBRIDGE w. STEVENS.

WVitn'esses;

JOHN: T. Fanny,

STEPHEN D. BROADBENT. 

